Accurate evaluation of the size and transmural extent of a myocardial infarction (Ml) can predict left ventricular remodeling and clinical prognosis. Early identification of patients with large transmural infarctions can guide initial aggressive medical therapy. Unfortunately, current imaging techniques are unable to distinguish between non-transmural and transmural infarctions as they cannot take into account through plane motion. Since myocyte contraction occurs along the myofibril direction which changes from epicardium to endocardium, we hypothesize that comprehensive 3D assessment of left ventricular mechanics can determine the extent of injury. This hypothesis will be tested by: 1) quantifying 3D transmural myocardial strain using 3D echocardiograms and a biomechanical model in an established canine infarct model and 2) correlating intramural myocardial strain and material parameters with myocardial flow and histologically determined extent of myocardial injury. As part of testing the hypotheses, the computed myocardial strains will be validated experimentally using sonomicrometer crystals. This research will investigate the basic science and develop the technology for a clinically very useful bedside diagnostic procedure. [unreadable] [unreadable]